This project is part of a program project directed toward assessing cardiac effects of particulate and other ambient air pollutants. In this project active elderly adults living in the communities of Boston and Steubenville have attended 12 weekly sessions including approximately 40 minutes of Holter monitoring, blood pressure, and oximetry evaluation before, during, and after outdoor exercise. To investigate the relation of air pollution to cardiac and pulmonary rehabilitation, a second portion of this study involves abstraction of blood pressure and symptom data and downloading of available repeated measures telemetry data in two populations. These populations include: 1) 200 outpatients attending 8 to 36 repeated weekly exercise training sessions in a major hospital cardiac rehabilitation unit.